Boil macaroni in salted water until just tender. Do not overcook. Drain and set aside. Slightly firm pasta works best for baking later and keeps texture perfect.

In a pan, melt butter over medium heat. Add flour and whisk until smooth. Slowly add milk and cream. Cook until thick and creamy without lumps.

Add cheddar, Gruyère, and parmesan cheese. Stir until melted. Add salt, pepper and mustard powder. Mix well to create a smooth and rich cheese sauce.

Add cooked pasta to the cheese sauce. Mix until fully coated. Make sure every piece of pasta is covered with creamy sauce for best flavor.

Pour the mixture into a greased baking dish. Spread evenly with a spatula. This helps the dish bake evenly and gives a nice texture on top.

Cover the dish with foil or plastic wrap. Place it in the refrigerator overnight. This step helps flavors blend and creates a richer, deeper taste.

Preheat your oven to 180°C (350°F). Remove the dish from the fridge and let it sit at room temperature for 15 minutes before baking.

Bake uncovered for 30–35 minutes. The top should be golden and slightly crispy. The inside should stay soft, creamy and perfectly cooked.

Let it rest for 5–10 minutes before serving. This helps the sauce thicken slightly. Serve warm and enjoy this classic comfort food dish.